The trend of miniaturization of parts is a recognized need in today's highly complex world. This trend brings with it the need for developing efficient ways to produce smaller components to higher tolerance and specification levels. Micromachining is one solution to achieving this need, yet in today's conventional machine shops, the means for securing miniature parts to commercially available machine tools are very limited or nonexistent. Although small collets, chucks, mandrels and face plates work well for turning diameters or threading thin rods in conventional tooling machines, when specifications require multiple machining operations with high tolerance levels on the order of millimeter-sized parts or geometrically diverse parts, even collets chucks, mandrels and face plates are inadequate.
Securing and positioning extremely small parts within a tooling machine (such as a lathe, polisher or jig bore) for precise machining is very difficult if not sometimes impossible to achieve. Some commercial lathe tooling machine manufacturers include Levin, Louis & Sons, Inc., Servo Products Company and Minitool, Inc. This difficulty is further compounded when the parts require submicrometer tolerances, when such parts are required to be geometrically diverse or when the same miniature part requires machining on several surfaces.
In conventional practice, miniature blank parts (i.e., the part does not have a pattern or design) are secured to the tooling machine with a collet (which is a split, cone-shaped sleeve) for the initial machining process, and then has to be glued (e.g., by epoxy) to a mandrel or substrate and accurately aligned with a microscope for any additional machining processes. This process is inefficient and time consuming. Even when a collet is used, the accuracy of the part's correct alignment is compromised. Further, use of a collet requires removal, reversal, coordinate repositioning and precise reattachment of the part blank to a tooling machine's spindle center line for multistep operations.
Additionally, when the part requires additional machining processes, realignment of the glued part is very difficult, depends on the operator's skill in reintroducing the part back on the tooling machine and is equally difficult when it comes to removing the part from the tooling machine. While traditionally, vacuum forces are used to retain larger parts within the tooling machine, such forces are too weak to retain miniature parts in the tooling machine when the tooling machine applies any molding or cutting force. As such, under conventional practice, the amount of glue applied, the determination of the position of the part relative to the tooling machine, and the necessary repositioning of the part for additional machining may cause tolerance inaccuracies and processing difficulties resulting in scrap parts.
Typically, the greatest source of errors with conventional part holders is in relocating a part for subsequent fabrication steps (e.g., additional machining on a part). During additional fabrication steps, the accuracy of the machining is highly dependant upon the operator's skill, experience and finesse, but even without special effort, an operator can only usually achieve about 25 micrometers of accuracy. The present invention, in contrast, improves the art by allowing the locator to be reattached to a kinetic mount on a tooling machine with a significantly greater positioning accuracy (preferably about 0.25 micrometer or less). Furthermore, the alignment of the part for subsequent operation does not require a skilled operator and could be accomplished robotically.
Accordingly, it is an object of the present invention to provide a device which enables precision machining of complex miniature parts which is adapted to work with conventional tooling machines.
It is a further object of the present invention to provide a device which is adapted to be secured to a tooling machine, and which enables an operator to achieve precision machining with an accuracy of less than about 0.25 micrometer error.
It is also an object of the present invention to provide a device which is adapted to securely attach to a tooling machine for a single machining process, and which can removed and inserted into another tooling machine (or the same tooling machine) to allow additional machining on other surfaces of the miniature part without relocating the part from the device between machining processes.
It is also an object of the present invention to provide a device which is capable of milling precise patterns, such as required for optics or semiconductor technology, on several surfaces of a miniature part precisely and without any need to handle any surface of the part, while relaying highly specific tolerances to the part.
It is also an object of the present invention to provide an efficient device adapted to precisely mill a part in a tooling machine, which eliminates the cost and time of tool realignment and machine setup when a subminiature part requires additional machining on other surfaces of the part.
It is further an object of the present invention to provide an apparatus which makes precision micromachining more efficient in time and cost, requires less skill-intensive tasks and reduces scrap parts.
A further object of the present invention is to provide an apparatus which can function to precisely hold two or more separate parts during assembly steps.
A final object of the present invention is to provide an apparatus which can hold a blank upon which multiple parts are fashioned where selective and precise access to the part to be worked upon is accomplished by the apparatus.
These objects, as well of others evident to one of ordinary skill in the art, are accomplished by the invention described more fully herein.